Illinois Administrative Code
Title 83 - PUBLIC UTILITIES
Part 650 - UNIFORM SYSTEM OF ACCOUNTS FOR SEWER UTILITIES
Subpart B - ADDITIONS TO AND DELETIONS FROM NARUC UNIFORM SYSTEM OF ACCOUNTS
Section 650.204 - General Instructions with Respect to Structures and Equipment

a) With respect to structures and equipment, treat as retirement units any item of property which is readily separable from and separately useful from the larger assembly of which it forms a part and which has a life of several years. It is, of course, contemplated that consideration will be given to the cost of an item and that certain items otherwise meeting the above distinction but which cost $100 or less would not be considered a retirement unit (see Note at Accounting Instruction 19(3)).

b) Treat, also, as retirement units portions of structures or equipment replaced in cases where the replacement operates to extend the life of the structure or equipment or where itis necessary to record the replacement in the plant accounts in order that the records may, as nearly as practicable, show the cost of the structure or equipment as it actually exists.

c) Wherever appropriate, the retirement of any unit of property in the structures or equipment accounts shall include all costs of associated items which pertain solely to that unit, such as the costs of foundations; supports, ladders, runways, enclosures, guards; driving mechanisms; indicating, recording and measuring devices with their mountings; starting, control, regulating, protective, and safety devices; switchboards; special lighting conduits and wiring; pipes; ducts; spouts; chutes; hoppers; etc.